Gastight feedthrough

ABSTRACT

A switchgear assembly operable with compressed gas is provided with a gastight feedthrough arrangement for accommodating the passage of a plunger through the wall of a gas vessel of the assembly. The gastight feedthrough arrangement includes two annular members mounted on the wall in surrounding relation to the plunger and at least two rubber-elastic sealing rings are arranged in each one of the annular members for sealably engaging the plunger. A glide bearing is also mounted in each one of the annular members for slideably holding the plunger and the annular members are arranged in the wall so as to be axially spaced with respect to each other for defining a space therebetween in surrounding relation to the plunger for receiving a grease cushion therein.

United States Patent Thurk et al.

GASTIGHT FEEDTHROUGH Inventors: Gerhard Thurk; Reinhard Lekar,

both of Berlin, Germany Assignee: Siemens Aktiengesellschaft, Munich,

Germany Filed: Mar. 13, 1974 Appl. N0.: 450,881

Foreign Application Priority Data Mar. 27, 1973 Germany 2315732 US. Cl200/148 R; 200/302; 277/30; 277/128 Int. Cl. H0lh 33/02 Field of Search200/148 R, 150 R, 302; 277/30, 3, 135, 128

References Cited UNITED STATES PATENTS July 15, 1975 3,395,260 7/1968Hamlin ..200/302 3,810,634 5/1974 Hakansson ..277/3 PrimaryExaminer-Robert S. Macon Attorney, Agent, or FirmKenyon & Kenyon ReillyCarr & Chapin ABSTRACT A switchgear assembly operable with compressedgas is provided with a gastight feedthrough arrangement foraccommodating the passage of a plunger through the wall of a gas vesselof the assembly. The gastight feedthrough arrangement includes twoannular members mounted on the wall in surrounding relation to theplunger and at least two rubber-elastic sealing rings are arranged ineach one of the annular members for sealably engaging the plunger. Aglide bearing is also mounted in each one of the annular members forslideably holding the plunger and the annular members are arranged inthe wall so as to be axially spaced with respect to each other fordefining a space therebetween in surrounding relation to the plunger forreceiving a grease cushion therein.

5 Claims, 2 Drawing Figures PNENTEDJUL 15 ms SHEET Fig. 2

GASTIGI-IT FEEDTHROUGH BACKGROUND OF THE INVENTION The invention relatesto a gastight feedthrough of a plunger which is movable relative to thewall of a gas vessel of an electric switchgear assembly operating withcompressed-gas. The plunger can actuate devices for indicating theswitch position of a compressed-gas circuit breaker with a closed gascirculating system.

Deutsche Offenlegungsschrift 1,690,061 discloses a gastight feedthroughof this kind wherein the plunger is surrounded by a hollow, cylindericalrubber-elastic member which is sealed at its one end against the plungerand at its other end, against the wall of the vessel, and which isbraced against radial forces by metal parts arranged concentrically toit.

In this manner, the movable plunger is sealed at the penetration point,so that the compressed gas is separated from the surrounding atmosphere.The known feedthroughs should on the one hand, impede the movement ofthe plunger as little as possible and, on the other hand, should begastight. It is further known to seal the plungers of the movablecontacts of vacuum switch vessels with metal bellows.

SUMMARY OF THE INVENTION It is an object of the invention to provide animproved gastight feedthrough arrangement for accommodating the movementof the plunger of the kind referred to above. It is another object toprovide such a gastight feedthrough arrangement which is easilymaintained.

The gastight feedthrough arrangement according to the invention includestwo annular members surrounding the plunger and connected with the wallof a gas vessel of the corresponding switchgear assembly. Each of theannular members carries a slide bearing and at least two rubber-elasticsealing rings for the plunger. The annular members are displaced in theaxial direction in such a manner that they form a cavity surrounding theplunger to receive a grease cushion.

The invention makes it possible to achieve an operationally reliablefeedthrough which is gastight over extended periods of time and iseasily maintained. The guidance of the plunger and its sealing by therubberelastic sealing elements is accomplished by the two an nularmembers. An additional sealing is obtained by the grease cushion whichis arranged between the two annular members and the plunger.

The two annular members can be fastened detachably on opposite sides ofthe wall, each being advantageously fastened to the wall by its ownfastening means. This allows maintenance work to be performed withrespect to the feedthrough while keeping up the pressure in thepressurized space of the switchgear. Thus, the feedthrough can bemaintained by filling the same with grease and, if necessary, also toreplace part of the sealing elements.

In a preferred embodiment of the gastight feedthrough according to theinvention, the annular members each have a projecting flange rim, whichis intended to make contact with parts of the wall. It is particularlyadvantageous if the flange rim is pressed against the wall with asealing element interposed.

Although the invention is illustrated and described herein as a gastightfeedthrough, it is nevertheless not intended to be limited to thedetails shown, since various modifications may be made therein withinthe scope and the range of the claims. The invention, however, togetherwith additional objects and advantages will be best understood from thefollowing description and in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram,partially in section, of an electric switchgear assembly equipped with agastight feedthrough arrangement according to the invention.

FIG. 2 is a schematic diagram, partially in section, showing details ofthe gastight feedthrough arrangement according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Thecompressed-gas circuit breaker shown in FIG. 1 is designated withreference numeral 1 and can be constructed as two pressure breakers, forexample, for operation at 220 kV, or, also as a blast-piston breaker.The breaker includes two electrically series-connected switches locatedin switching chambers 2, 3. The switching chambers 2, 3 are mounted onmutually opposite sides of an actuator housing designated as the breakerhead 4 mounted on a-support insulator 5. The support insulator 5 is madehollow and surrounds an actuator rod 6 of electrically insulatingmaterial which is guided so that it can move back and forth in thedirection of the arrow 40 for operating the switches in the switchingchambers 2 and 3. Insulating gas, for instance sulfur hexafluoride, isprovided in the interior 7 of the support insulator 5 at a pressure of 4bar, for example. The insulating gas can also be used for are quenchingin the switching chambers 2 and 3.

The support insulator 5 is mounted on a housing 8 wherein a device 9 forindicating the switch position of the compressed-gas circuit breaker 1is provided. The housing 8 is mounted on a frame 10 supporting thecircuit breaker from below which also contains the drive 11 for thecompressed-gas circuit breaker. The drive can be constructed in themanner of a double-action actuator cylinder and may be operatedpneumatically or hydraulically. I

The electrically insulating actuating rod 6 is coupled to a plunger 12movable relative to the wall 13. In the wall 13, a gastight feedthrough14 is provided which will be described more fully in connection withFIG. 2.

Referring now to FIG. 2, two annular members l5, 16 are connected withthe wall 13 and surround the plunger 12 and carry slide bearings 17 and18, respectively. The two annular members 15 and 16 each have tworubber-elastic sealing rings 19, 20 and 21, 22 which are pressed againstthe cylinderical surface of the plunger 12.

The two annular members 15 and 16 are detachably fastened on oppositesides of the wall 13 by means of screw elements 23 and 24 and arearranged displaced from each other in the axial direction in such amanner that they form a cavity 25 surrounding the plunger to receive agrease cushion 26. Because of the fact that the annular members 15 and16 each have their own fastening elements 23 and 24, they can beindividually detached from the wall 13.

Each of the annular members 15 and 16 has a radially projecting flangerim 27 and 28 which is intended for making contact with parts ofthet-gwall l3, -The flange ment 29 interposed while, the flange rim 28is pressed against the wall 13 with a similar sealing element 30interposed.

The gastight feedthrough according to the invention affords the specialadvantage that the essential parts of the gastight feedthrough which aresubject to wear can be inspected and maintained by loosening the annularmember 16 while maintaining the pressure in the compressed-gas space onthe side close to the annular member 15.

Thus, it is possible without difficulty to replace the sealing element20 of the annular member 15 by loosening the fastening elements 31, 32to replace the grease 26 as well as the sealing elements 21 and 22 inthe annular member 16, and the slide bearing 18.

What is claimed is:

1. In a switchgear assembly operable with compressed gas, the assemblybeing equipped with a gas vessel having a wall and a device such as forannouncing the switch position or the like, the device being actuable bya plunger movable with respect to the wall of the gas vessel, a gastightfeedthrough arrangement for accommodating the passage of the plungerthrough the wall, the gastight feedthrough arrangement comprising: twoannular members mounted on the wall in surrounding relation to theplunger; at least two rubber-elastic sealing rings arranged in each oneof said annular members for sealably engaging the plunger; and a glidebearing also mounted in each of said annular members for slidablyholding the plunger, said annular members being arranged in the wall soas to be axially spaced with respect to each other for defining a spacetherebetween in surrounding relation to the plunger for receiving agrease cushion therein.

2. The gastight feedthrough arrangement of claim 1, each of said annularmembers being removably mounted on respective sides of the wall facingaway from each other.

3. The gastight feedthrough arrangement of claim 2, fastening meanscorresponding to respective ones of said annular members forindividually removably fastening the same. v

4. The gastight feedthrough arrangement of claim 1, each of said annularmembers having a flange-like rim projecting radially therefrom forcontacting a portion of the wall.

5. The gastight feedthrough arrangement of claim 4 comprising sealingmeans interposed between said rim portion and the wall portion, andmeans for tightly securing said flange-like rim to the wall so as topress said sealing means between said rim portion and the wall

1. In a switchgear assembly operable with compressed gas, the assemblybeing equipped with a gas vessel having a wall and a device such as forannouncing the switch position or the like, the device being actuable bya plunger movable with respect to the wall of the gas vessel, a gastightfeedthrough arrangement for accommodating the passage of the plungerthrough the wall, the gastight feedthrough arrangement comprising: twoannular members mounted on the wall in surrounding relation to theplunger; at least two rubber-elastic sealing rings arranged in each oneof said annular members for sealably engaging the plunger; and a glidebearing also mounted in each of said annular members for slidablyholding the plunger, said annular members being arranged in the wall soas to be axially spaced with respect to each other for defining a spacetherebetween in surrounding relation to the plunger for receiving agrease cushion therein.
 2. The gastight feedthrough arrangement of claim1, each of said annular members being removably mounted on respectivesides of the wall facing away from each other.
 3. The gastightfeedthrough arrangement of claim 2, fastening means corresponding torespective ones of said annular members for individually removablyfastening the same.
 4. The gastight feedthrough arrangement of claim 1,each of said annular members having a flange-like rim projectingradially therefrom for contacting a portion of the wall.
 5. The gastightfeedthrough arrangement of claim 4 comprising sealing means interposedbetween said rim portion and the wall portion, and means for tightlysecuring said flange-like rim to the wall so as to press said sealingmeans between said rim portion and the wall portion.